Organo silicon compounds and method of making them



Patented Oct. 9, 1945 ORGANO SILICON COMPOUNDS AND METHOD OF MAKING THEM Robert F. Fleming, Jr., Laurens, S. 0., assignor to Corning Glass Works, Corning, N. Y., a corporation of New York No Drawing. Application September 25, 1942, Serial No. 459,738

' Claims. (01.260-462) This invention relates to organo-silicon compounds and methods of preparing them.

One of the objects of my invention is to provide a new method of preparing organo-silicon compounds of the type XH-SiYn, where X may be the same or different organic radicals; Yv represents a member of the group consisting of halogens and alkoxy radicals; and where n equals 0, 1, 2, or 3.

Another object of my invention is to employ organo-lithium compounds for introducing organic radicals into silicon compounds.

Still another object of my invention is to prepare new compositions of matter by means of the interaction of organo-lithium compounds and silicon compounds.

A further object of my invention is to prepare aminoaryl and substituted aminoaryl silicon compounds.

In accordance with my invention I have provided a new method of introducing organic radicals into silicon compounds having halogens or alkoxy radicals attached directly to the silicon. This method comprises in general reacting organo-lithium eompoundsof the type RLi, where R is an organic radical, with compounds of the type xi-nSiYn, where X is an organic radical; Y represents a member of the group consisting of halogens and alkoxy radicals; and n represents an integer from 1 to 4 in accordance with the following equation In general the product resulting from this reaction comprises a mixture of the various possible R substituted silicon compounds and not the single one indicated in the equation. In carrying out the reaction, the RH compound is dissolved or suspended in any suitable organic solvent such as diethyl ether and is then added slowly to an ice cold solution of the silicon compound in the same organic solvent. The solution is stirred during the reaction and protected against oxygen and moisture in order to enhance the yield. The LiY compounds being insoluble in the organic solvent readily settle out and may be removed by filtration. The remaining products are then separated by fractional distillation.

. If desired, the above procedure may be modifled in the following manner. Instead of first preparing the RM compound by reacting lithium with the corresponding organic halide, the latter is added slowly with vigorous stirring to a or substituted silicon halides are used that the first procedure gives better results for the reason that the presence of silicon halides or substituted silicon halides interferes with the formation of the RH compound and the .Li present promotes condensation of the substituted silicon halides to give SiSi linkages thereby reducing the yield of the desired product. With the alkoxy silicon compounds this complication does not occur so the organic halide can be added directly to a mixture of Li and a silicon alkoxide in some inert solvent with good yields of the desired product.

The choice of solvent dependsupon the particular organic halide to be used. Generally speaking diethyl ether gives better yields of organo-silicon compounds, although in some cases either benzene or low boiling petroleum ether, alone or mixed with diethyl ether can be used to advantage.

For a better understanding of my invention the following examples are given. In the examples abbreviations are to designate certain elements and groups, thus: methyl (Me); ethyl (Et); phenyl (o).

Example 1 Methyllithium was prepared by reacting lithium and MeCl in diethyl ether. The ether solution of Men was then added slowly with stirring to an ice-cold solution of 6.5 g. of sick in 50 cc. of ether. During the entire procedure the reactants were protected from moisture and oxygen. Most of the ether was removed by distillation and the residue was treated with dry CaHsOH to form the silicon esters. The mixture was then hydrolyzed by the addition of water and alkali. An oily product was isolated from this reaction mixture which was a copolymer containing dimethyl-silicon and mono-methyl silicon structural units.

Example 2 Example 3 An ether solution of EtLi was run slowly into a solution of 1 mole of SiC1a in four volumes of ether.

at the boiling point of ether. The solution was filtered; the solvent was removed; and the resulting liquid was fractionated at atmospheric pressures to give EtSiCh having a boiling range of about 225-235 C. at 760 mm.

The reaction was allowed to proceed Example 4 Example 5 A solution of .061 mole of m m 100 cc. of

ether was added slowly with stirring to .2 mole of SiCl4 diluted with 100 cc. of ether. The reaction mixture was cooled in an ice bath. Fil- A tration and fractional distillation gave SiCla having a boiling range of 195-200 C. at 760 mm.

Example 6 The above experiment was repeated except that a mixture of equal parts of ether and benzene was used as a solvent for the preparation of Li from 4:01 and Li. In this case SiC1a having a boiling range of 195-200 C. at 760 mm. was isolated.

Example 7 Ethyllithium was prepared by reacting EtCl and Li in ether. The resulting solution was shown by titration to contain .082 mole of the product. It was then added slowly with stirring to a cold solution containing 17.6 g. of SiC1a in 75 cc. of ether. The mixture was filtered and fractionated. In this way a liquid having a boiling range of 90-110 C. at 30 mm. was obtained. A sample was analyzed for chlorine and found contain 38%. This corresponds to a miiyr of 75% EtSiClg and 25% 1181013.

' Example 8 A solution of .079 mole of EtLi in ether was prepared in the usual manner and added slowly with stirring to .2 moles of SiCh dissolved in 75 cc. of ether. The reaction mixture was cooled with ice. When the mixture was filtered and fractionated, EtSlCls having a boiling point of 100 "C. at 760 mm. and EtzSiCla having a boiling point of 130 C. at 760 mm. were isolated.

Example 9 1.4 grams of Li, 23 cc. SiCh and 50 cc. of either were placed in a three-neck flask and 12.6 g. of undiluted benzyl chloride were added slowly. During the reaction the mixture was stirred and warmed so that the ether refluxed. The heating was continued overnight. The mixture was filtered and fractionally distilled. This gave CHuSiCl3.

Example 10 It is known that p-bromoanisole reacts with Li to give a mixture of 3 bromo-, fi-methoxyphenyllithium and 4-methoxyphenyllithium according to the following equations.

The second reaction predominates.

To 1.4 g. of L1 in 50 cc. of ether a solution of 18.7 g. of p-bromoanisole in 40 cc. of ether wasadded slowly with stirring. The stirring was continued overnight. A dark brown solution I acted p-bromoanisole, a dark brown liquid having a boiling range of -200 C. at 13 mm. was obtained. This was redistilled and the ample h vin a boiling range of -140 C. was taken for analysis. Qualitative tests showed the presence of bromine. -Analysis for silicon in terms of S102 gave 19.2% S102; silica calculated for -sio1 Example 11 To a mixture of 14 g. of Li, .2 mole of Si(OEt)4 and 44 cc. of ether, 11.2 g. of Cl was added slowly with stirring. After all the Cl had been added the stirring was continued overnight. The mixture was filtered and the ether was removed at atmospheric pressure. The residue was then fractionated at 15 mm. A colorless liquid having a boiling point of 120 C. at 15 mm. was obtained. Analysis showed 25.1% S102; calculated silica for Si(OEt)a is 25%.

Example 12 MeSi(OEt)a (.2 mole) was diluted with an equal volume of ether and 1.4 g. of Li was added. The mixture was stirred and warmed as 11.2 g. of 4:01 were dropped in. After three hours, the reaction was complete. The mixture was filtered and fractionated to give a colorless liquid having a. boiling range of 105-110 C. at 13 mm. Analysis showed 28.8% S102. Theoretical SiOa for MeSi(0Et)a is 28.6%.

Example 13 A mixture of 1.4 g. of Li, 30 cc. of Si(OEt)4, and 20 cc. of ether was placed in a three-neck flask. The stirrer was started and 20 g. of p-bromodimethylaniline in 50 cc. of ether was added at such a rate that the ether refluxed gently. When the mixture was filtered and fractionated, a light yellow liquid having a boiling range of -182 C. at 14 mm. was isolated. Analysis showed 21.2% S102. Theoretical $10: for MezNC6H4Si(OEt)a is 20.9%.

Example 14 To a mixture of 1.4 g. of L1, 30 cc. of Si('OEt)4, and 20 cc. of ether a solution of 17.1 g. of p-CI-IaCaH4Br in 40 cc'. of ether was added slowly with stirring. The mixture was warmed during the reaction. Filtration and fractionation resulted in the separation of a colorless liquid which boiled at 137 C. at 14 mm. Analysis showed 23.8% S102. Theoretical $102 for CHaCeI-IeSi (OED 3 Example 15 Lithium (1.4 g.) was placed in a'solution of 30 cc. of SKOEth in 20 cc. of ether and the mixture was stirred and warmed as 18.5 g. of 2- bromo, 1,4-dimethylbenzene in 30 cc. of ether were slowly added. The mixture was filtered and fractionally distilled. A colorless liquid boiling at 150 C. at 23 mm. was isolated. Analysis showed, 22.8% $102; theoretical SiO: for

(CH3) aCeHaSi (OEt) 3 Example 16 To a mixture of 1.4 g. of Li, 30 cc. of 81(0Et) 4. and 20 cc. of ether, 9. solution of 23.3 g. of p-bromodiphenyl was added slowly with stirring. After the reaction was complete the mixture was filtered and distilled. This gave a colorless liquid having a boiling range of 210-2l5 C. at 13 mm.

Analysis showed 18.8% $102; theoretical SiO: for

CcHs-CeH4Si(0Et)a is 19%.

Example '17 A solution of 17.2 g. of p-bromoaniline in 50 cc. of ether was added with stirring to a mixture of 1.4 3. Li, 45 cc. of Si(OEt)4. and 20 cc. of

. EtsO. The reactants were maintained at 35 for I'IiNClHtSl (OEt) a Example 18 A solution of .094 mole of p-dimethylaminophenyllithium was prepared by reacting 1.4 g. of Li with 20 g. of p-bromodimethylaniline in ether. The solution was then slowly added with stirring to 0.028 mole of Si(Et)4 in 25 cc. of ether and the mixture was refluxed overnight. The ether and low boiling fractions were removed and a yellow viscous oil boiling about 300 C. remained. This was treated with aqueous alcohol and after removal of the water and alcohol a yellow crystalline material remained. The silicol was distilled and was found to boil at 275-280 C. at 12 mm. Analysis showed 14.65% 3102; calculated 810: for [(CHshNCaHd-a SiOH is 14.8%.

Example 19 Amyllithium was prepared by reacting n-amyl chloride with Li in ether. To a solution of .218 mole of amyllithium in 30 cc. of ether, .103 mole of benzyl alcohol in 100 cc. of ether was added slowly with stirring. The reaction mixture was cooled in an ice bath during the addition of the alcohol. The mixture was refluxed for 20 hours and then run into a solution of .2 mole of Si(OEt)4 in 50 cc. of ether. After 3 hours heating, the solution was cooled with ice and dry HCl was passed through to remove the Li alcoholaites. The solution was filtered, the ether was removed, and the residue was fractionated. A yellow viscous oil boiling 200-210 C. at 15 mm. was isolated. Analysis showed 17.8% S102; calculated SiOz for (HOCHzCsHUaSKOEt): is 18.1%.

By the above method I have been able to prepare compounds which were hitherto only dimcultly prepared by means of the magnesium Grignard reaction and in some cases impossible to prepare. My method also has the advantage of the reactivity. of the lithium compounds. Furthermore, since the lithium salts do not form etherate with ether, the reaction proceeds with celerity and in a clean-cut fashion owing to the absence of bulky etherates which normally interfere with the progress of the magnesium Grignard reaction.

By my method alkyl groups such as methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, terbutyl, amyl, etc.; substituted alkyl such as benzyl: aryl groups such as phenyl, naphthyl, anthracyl, tolyl, xylyl, biphenyl, etc. or substituted aryl groups such as anisyl, aminophenyl; dialkylaminophenyl, dihydroxyphenyl, w-hydroxytolyl, etc. may be introduced into silicon compounds having one or more halogen atoms or alkoxy groups attached directly to the silicon.

On the strength of the evidence provided by the examples given above it is believed that any organic radical capable of forming an organolithium compound with lithium may be introduced into silicon compounds having one or more halogen atoms or alkoxy groups attached directly to the silicon by means of the above described methods.

The organo-silicon compounds prepared by my new method as illustrated in the above examples are extremely useful as intermediates in the production of organo-silicones. The latter are polymerizable substances having a wide variety of uses in the fields of coating compositions,

3. The method of preparing a compound having the formula (CH3)2NC6H4Si(OC2H5)3 which comprises reacting together lithium, ethyl silicate and p-bromodimethylaniline, heating the reaction mixture, and fractionally distilling the liquid portion of the reaction product to recover the liquid boiling between 180-182 C. at 14 mm. of Hg.

4. The method of preparing a, compound having the formula H2NCcH4Si(OC2H5): which comprises reacting together lithium, ethyl silicate and p-bromoaniline, heating the reaction mixture, and fractionally distilling the liquid portion of the reaction product to recover the liquid boiling between -150 C. at 14 mm. of Hg.

5. The method of preparing organo-monosilanes which comprises reacting lithium and an organic halide whose organic substituent is selected from the class consisting of amino-aryl and N-alkyl-amino-aryl radicals with ethyl orthosilicate.

6. The method which comprises reacting ethyl orthosilicate with lithium and an amino-aryl halide.

7. The method which comprises reacting ethyl of being carried out at low temperatures becauseorthosilicate with lithium and an N-alkyl-amino aryl halide.

8. A compound having the general formula. RSi(O-Alkyl)a, where R represents an organic radical which is selected from the class consisting of amino-aryl and N-alkyl-amino-aryl radicals and which is attached to silicon through carbon-silicon linkage.

.9. A compound having the general formula RSi(0-C:Hs)a, where R represents an organic 10 

